[SFDXA] ARLP012 Propagation de K7RA

Fri Mar 19 21:27:26 EDT 2021

> SB PROP @ ARL $ARLP012
> ARLP012 Propagation de K7RA
> 
> ZCZC AP12
> QST de W1AW  
> Propagation Forecast Bulletin 12  ARLP012
> From Tad Cook, K7RA
> Seattle, WA  March 19, 2021
> To all radio amateurs 
> 
> SB PROP ARL ARLP012
> ARLP012 Propagation de K7RA
> 
> Average daily sunspot numbers this week rose just a little, from
> 18.4 to 19, and average daily solar flux changed from 78.9 to 78.1.
> Solar activity remains low.
> 
> Note the vernal equinox, (the first day of spring in the Northern
> Hemisphere) occurs at 0937 UTC on Saturday, March 20.  Both the
> Southern and Northern hemispheres will be bathed in approximately
> equal amounts of solar radiation, which has a positive effect of HF
> propagation.
> 
> On March 17 and 18, the daily sunspot number was only 12 on both
> days, but the total sunspot area rose from 50 to 200
> micro-hemispheres.  Sunspot area was last at this level on February
> 25.  You can see daily sunspot area along with sunspot numbers and
> solar flux at ftp://ftp.swpc.noaa.gov/pub/indices/DSD.txt .
> 
> Average daily planetary A index rose from 7.6 to 10.3, and average
> daily middle-latitude A index increased from 6.1 to 7.3.  Solar wind
> on March 14 drove the planetary A index to 25, and Alaska's College
> A index was 37.
> 
> On Wednesday March 17 Spaceweather.com warned that minor geomagnetic
> unrest is expected on March 18, due to a co-rotating interactive
> region that will disturb our magnetic field.  "CIRs are transition
> zones between fast and slow-moving solar wind streams.  Plasma piles
> up in these regions, creating shock-like density gradients that
> often do a good job sparking auroras."
> 
> On March 18 Spaceweather.com reported, "NOAA forecasters say that a
> minor G1-class geomagnetic storm is likely on March 20 and 21 when a
> stream of high-speed solar wind hits Earth's magnetic field.  The
> gaseous material is flowing faster than 600 km/s from a southern
> hole in the sun's atmosphere."
> 
> The latest forecast from the US Air Force Space Weather Squadron
> predicts solar flux at 72 on March 19 to 21, 70 on March 22 to 26,
> 76 on March 27, 75 on March 28 through April 1, 78 on April 2 and 3,
> then 70, 74, 76 and 72 on April 4 to 7, 71, 72 and 70 on April 8 to
> 10, 71, 72 and 71 on April 11 to 13, then 73, 76, 75 and 76 on April
> 14 to 16.  Solar flux is expected to hit a high of 81 on April 19.
> 
> Predicted planetary A index is 12, 24, 20, 15, 12, 8 and 10 on March
> 19 to 25, 5 on March 26 to 27, 25 on March 28, 20 on March 29 to 30,
> then 10, 5, 15 and 8 on March 31 through April 3, 5 on April 4 to 7,
> then 15, 18, 20, and 15 on April 8 to 11, then 8, 5 and 8 on April
> 12 to 14, and 20 on April 15 and 16 and 18 on April 17.  The A index
> may peak at 25 again on April 24.
> 
> More about the Air Force and space weather: https://bit.ly/30Zrzzv
> 
> Geomagnetic activity forecast for the period March 19 to April 13,
> 2021 from F. K. Janda, OK1HH.
> 
> "Geomagnetic field will be
> Quiet on:  March (27,) April 1, 4, 6, 12
> Quiet to unsettled on:  March 25 and 26, April 3, 5, 7
> Quiet to active on:  March 22 to 24, 31, April 13
> Unsettled to active:  March 21, April 2, 8 and 9, 11
> Active to disturbed:  March (19 and 20,) 28 to 30, April 10
> 
> Solar wind will intensify on:  March (19,) 20 to 22, (23, 27,) 28
> and 29, (30, April 1 and 2, (3 to 5, 8,) 9 and 10, (11)
> 
> Parenthesis means lower probability of activity enhancement.
> Predictability of changes remains very low, as indicators remain
> ambiguous."
> 
> At 2358 UTC on March 17 Australia's Space Weather Services sent this
> alert:
> 
> "A large Southern Polar coronal hole with low latitude extensions
> will become geoeffective with the CIR possibly arriving from late on
> UT day 19 March, causing unsettled to active conditions.  The HSS
> from the coronal hole is expected to follow on UT day 20 March,
> causing active conditions with the possibility of a G1 minor storm.
> Active conditions are expected to continue on 21 March, Auroras may
> be visible from Tasmania at night on 19-20 March."
> 
> Dave Bono, K6OAK in Fremont, California reports:
> 
> "On Monday March 15th just before 1900 UTC 6 and 10 meters were
> dead, but I noticed a few signals on 12M FT8, one being a fairly
> strong signal from VP8NO in the Falklands.  After a few attempts I
> was able to make contact and received a respectable -10 report.  I
> was running 50 watts into a ground mounted vertical antenna.  Not
> bad for a few minutes in the shack."
> 
> Mike, KA3JAW in Easton, PA (FN20jq) reports six meter activity:
> 
> On March 13 at 1627 UTC six meter sporadic-e began to appear on FT8
> 50.313 MHz with stations from the central states of IL, MO, KY, NE,
> IA and KS for over 3.5 hours from the first Es cloud formation.
> 
> 1659 UTC heard VO1SIX in Newfoundland, Canada (GN27jd) at 1090 miles
> coming in from 065 degrees azimuth from a second Es cloud formation.
> 
> 1830 UTC Es starts to spread out directly west into the central
> states of NE, IA and KS.
> 
> The farthest distance came from KQ0P (EM19wf) at 1109 miles, 271
> degrees azimuth with a signal of -6 dB while the radio power output
> was 15 watts using a half wave dipole at 6 feet above ground.
> 
> Remembering the 1989 Quebec event:
> 
> https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019SW002278
> 
> This article on solar activity has some interesting links:
> 
> https://bit.ly/3s2BksC
> 
> Historic sunspot activity going way, way back:
> 
> https://bit.ly/2QjJyP4
> 
> VA7JW gives an overview of the Dominion Radio Astrophysical
> Observatory at Penticton which supplies us with solar flux data:
> 
> http://archive.nsarc.ca/hf/drao_solar.pdf
> 
> For more information concerning shortwave radio propagation, see
> http://www.arrl.org/propagation and the ARRL Technical Information
> Service at http://arrl.org/propagation-of-rf-signals.  For an
> explanation of numbers used in this bulletin, see
> http://arrl.org/the-sun-the-earth-the-ionosphere.
> 
> An archive of past propagation bulletins is at
> http://arrl.org/w1aw-bulletins-archive-propagation.  More good
> information and tutorials on propagation are at http://k9la.us/.
> 
> Instructions for starting or ending email distribution of ARRL
> bulletins are at http://arrl.org/bulletins .
> 
> Sunspot numbers for March 11 through 17, 2021 were 23, 15, 12, 24,
> 24, 23, and 12, with a mean of 19.  10.7 cm flux was 78.2, 76.9,
> 81.1, 78, 74.8, 79.2, and 78.2, with a mean of 78.1.  Estimated
> planetary A indices were 4, 12, 17, 25, 7, 4, and 3, with a mean of
> 10.3.  Middle latitude A index was 3, 9, 13, 17, 5, 2, and 2, with a
> mean of 7.3.
> NNNN
> /EX